Polymer fibers with diameter in the micrometer and submicrometer range are raising an increasing interest, because of their smart properties useful for a wide class of applications, including textiles, microelectromechanical systems, sensors, and optoelectronic devices. Polymer nanofibers can be employed as building blocks for structurally reinforced composites, filtration membranes, and scaffolds for tissue engineering, smart clothes and protective wound dressing. They are able to capture aerosol particles, and they can find use as large-surface supports for enzymes and catalysts, matrices of electrolytes for high-performance batteries, sacrificial templates for nanofluidics, and active materials for electronic and photonic devices.
So far, the practically unique technique, by means of which one is able to fabricate polymeric nanofibers with low cost and high throughput is the electrospinning, which relies on the uniaxial elongation of a fluid polymer jet under an intense applied electric field. The electrostatic repulsive force between surface charges, and the concomitant evaporation of the solvent determine the stretching of the jet, thus achieving very long fibers, as thin as few tens of nm.